Bug 1986 fix:
(1) Using interface ICore containing all Karaf commands is not proper and brings failure, so seperate into two interfaces, IKarafCore and IKarafVLANService.
(IKarafCore is implemented in Controller.java, IKarafVLANService is implmented in VLANService.java)
(2) In blueprint.xml, the <property> can't be correctly referenced in Karaf, so solve by alternative approach -- in the doExecute(), get IKarafXXX interface to call)

Signed-off-by: ylhsieh <ylhsieh@itri.org.tw>